Impact of Genetic Variants in Mir-122 Gene and its Flanking Regions on Hepatitis B Risk

MicroRNAs are small non coding RNAs that are involved in gene expression regulation. Mir-122 was reported to inhibit hepatitis B virus (HBV), but little is known about the role of mir-122 polymorphisms on HBV infection development. This present study aimed to investigate the association between single nucleotide polymorphisms (SNPs) in mir-122 gene region with HBV infection. Study cases were HBV positive and negative individuals. 67 SNPs in mir-122 gene and its flanking regions were analyzed by sequencing method. mirVas software was used to assay the impact of polymorphisms on the secondary structure of mir-122 gene. 66 out of 67 studied SNPs were monomorphic and rs 17669 was the only polymorphic SNP in the studied population, with the T allele being four times more frequent than the C allele. However, there was no significant difference in alleles distribution between patient and control groups. Rs 17669 variant located near the mir-122 gene showed the highest impact for centroid, maximal expected accuracy, and minimal free energy structures in the arm, flank, and flank regions of mir-122, respectively. Therefore, rs17669 variant was predicted to exert an effect on mir-122 stability. The study of larger samples from different ethnicities may help to find a possible association between rs17669 genotype and HBV infection.